Curved stock grinder and sander



Dec. 31, 1935. w. s. STROM CURVED STOCK GRINDER AND SANDER Filed March 25, 193 5 5 Sheets-Sheet 1 INVENTOR 1 ram 7% ATTORNEYS Willi Dec. 31, 1935. w s STROM 2,026,258

CURVED STOCK GRINDER AND SANDER Filed March 25, 1955 3 Sheets-Sheet 2 2 I v 43 4.4 'Z-H- William gjgi'rom BY r-W ATTORNEYS I Patented Dec. 31, 1935 UNITED STATES PATENT OFFICE 5 Claims.

My present invention relates to the art of portable grinders and sanders and more particularly to a curved stock grinder and sander.

In industry there are many uses for a grinder 5 or sander which can be adjusted to, and will guide, the cutting wheel around a curve either convex or concave. Such a device is of particular value in ship work, for finishing curved surfaces of metal or wood, in the finishing of castings and, particularly, in the finishing of sheet metal work, of the latter especially automobile fender and body work. With my present device it is possible to so adjust the stock or guide means that a curve can be carefully followed. This is of particular value in the repair, straightening and refinishing of sheet metal work, Where the amount of metal to be removed is very little and where it is so difficult to hold the average grinder and direct it with suflicient accuracy so that a smooth unmarred surface results. With my grinder this is easily accomplished, even by a workman who is not highly trained.

The principal object of my present invention, therefore, is to provide a guide means for a grinder, or sander, or rotary cutting tool, that is readily adjustable so that the cutting wheel can be held a definite distance away from the body of the work to be finished.

A further object of my present device is to provide means whereby the cutting wheel may be accurately guided on curved surfaces.

Other and more specific objects will be apparent from the following description taken in connection with the accompanying drawings, wherein Figure 1 is an end elevation of my device showing the same as it would be adjusted for a concave surface.

Figure 2 is a side elevation of my device of the type which is driven by a flexible shaft.

Figure 3 is a fragmentary view, similar to Figure 1, with certain parts shown in section and showing the stock in the position adapting the tool for working on a convex surface.

Figure 4 is an end elevation, similar to Figure 2, but illustrating a unit motor drive instead of the flexible shaft arrangement of Figure 2.

Figure 5 is a cross-sectional View taken in the same sense as Figure 2 showing the various parts in cross-sectional view.

Figure 6 is a cross-sectional view taken along the line 6-6 of Figure 2.

Figure '7 is a cross-sectional view taken along the broken line 1-4 of Figure 2.

Figure 8 is fragmentary View showing, in top plan the extreme ends of the flexible and adjustable stock, or guide member.

Referring to the drawings, throughout which like reference characters indicate like parts, l0 designates the main frame of my device. This is provided with suitable journal l2 adapted to receive the bearings l4 and 15 which support the cutting wheel shaft l6. An upwardly extending, slotted guide member I0 is normally formed as part of member Hi to insure greater rigidity. At the opposite end of frame 10 there is secured a suitable handle and, disposed below the handle in the flexible shaft drive, is a centering block 22 and clamp means 23. Shimming 24 is disposed between frame [0 and block 22 so that adequate adjustment may be provided for flexible shafts 25 of different sizes. In the flexible shaft drive I prefer to employ a flexible coupling unit as 28. Adapted for vertical move- 1.

ment within guide member I8 is a stock supporting frame 30. This is moved within guide l8 by adjustable screw 32 and is locked in the desired position by the locking nut 34, as is probably best illustrated in Figure '7.

In the alternate arrangement shown in Figure 4 I provide, instead of the flexible shaft 26, an electric motor 36 having the driving pinion 31 operatively connected with the driven gear 38 by means of an idler 40. This arrangement requires a slight modification of frame I0. It has advantages, namely, that of cheapness and greater flexibility in use, but it is also heavier and for some purposes not so desirable as the form shown in Figure 2.

In either of the forms shown the stock, or guide means, is the same. It consists of a semicircular support means 42. This member is bifurcated at itslower extremity to provide the two feet 43 and 44 which are spaced sufliciently to permit straddling the cutting wheel 46 after the showing of Figures 4 and 5. Support member 42, while it might be made as a part ofmember is more preferably a separate member pivoted upon pin 41. This pin is fixedly secured within member 30 and is provided with a key pin 48. This key pin is adapted to engage slot 50 formed in member 42 and is held in the engaged position by compression spring 52. The purpose of this arrangement being to permit swinging member 42 and its connecting parts around through an arc of 180 degrees and then to reengage member 30 in a locked position. Fixedly secured to the bifurcated end of member 42 is a spring steel guide member or stock 54. This member has, at its outer end, a bearing member 56 which carries at its upper end a locking bolt 58. Bolt 58, in addition to passing through bearing 56, also passes through slots 60 and BI formed in the adjustable positioning members 52 and 63, respectively. These members in turn are pivotably secured to member 42 as at and 66, respectively.

Method 00 operation In using my device it is first determined on which side of the cutting wheel the guide member 54 is desired. This adjustment is effected by pressing member 54 downwardly against spring 52, swinging the same around to the position desired, then it is next necessary to determine the curvature which guide 54 is to assume. Usually this is best accomplished by laying the device on the work in question and bending the flexible member 54 until the adjustment is satisfactory and then clamping it in that position by means of clamping wing nut 68.

Then by suitable adjustment of screw 32 the cutting wheel is adjusted with respect to guide 5 3 and the device is ready for use. It is normally held with handle 20 and by handle it! which is adjustably positioned, being clamped in the desired position by screw ii. In some instances where it is desired to work near a flange it is sometimes desirable to attach to either of the feet 43 or 44, additional blocks and for this reason I have provided the tapped holes 12 to which the block may be secured.

The foregoing description and the accompanying drawings are believed to clearly disclose a preferred embodiment of my invention but it will be understood that this disclosure is merely illustrative and that such changes in the invention may be made as are fairly within the scope and spirit of the following claims:

I claim:

1. In a hand-tool, the combination with a main frame including a rigid post, of a guide frame including a yoke having a head movable on the post, a spring interposed between said head and a part of the post, and means for preventing rotary movement of the head on the post.

2. In a hand-tool, the combination with a main frame including a rigid post, of a guide frame including a yoke having a head movable on the post, a spring interposed between the head and a rigid part of the post, said head having an edge-notch, a pin rigid with the post and engaged in the notch, and a resilient flexible blade attached to the yoke.

3. In a hand tool, the combination with a main frame and its rigid post, of a guide frame including a yoke having a head movable on the post, a spring interposed between the head and a part of the post, said head having an edgenotoh, a transversely extending pin on the post engaged in the notch, a resilient flexible blade having one end attached to the yoke, a

pair of arms pivoted on the yoke and slotted at their free ends, an armon the blade, and clamping means for the three arms to secure the blade in adjusted position.

4. In a hand-tool, the combination with a main frame, an adjustable slide frame, means for securing the slide frame in adjusted position and a reversible guide frame having a supporting head, of a supporting post rigid with the slide frame, said head being mounted on the post and adapted to turn thereon, and,

the yoke adjacent the rotary tool, and cooperating means on the yoke and blade for holding the latter in adjusted position.

WILLIAM S. STROM. 

